Determination of tectonic and crust structure of the Marmara Seabasin using the WGM2012 gravity data

The aim of this study is to investigate the reasons for the positive gravity anomalies on the West Marmara and Çınarcık Basins and negative gravity anomalies on the Central Marmara Basin and the continuity of the Main Marmara Fault in the Marmara Sea. For this purpose, the average depth values of the inter–sedimentary layer, basement, Conrad and Moho interface topographies of the study area were calculated by applying the angular power spectrum to the Bouguer gravity data. Then, by applying a bandpass filter to the Bouguer gravity data, the gravity data of the inter- sedimentary layer, basement, Conrad and Moho interfaces in the study area were calculated. Obtained gravity data were evaluated with 3D inversion processes. In addition, in order to determine the lateral discontinuities of the units at shallow levels in the study area, the gravity data of these levels were evaluated by the total horizontal derivative method. However, the continuity of the Main Marmara Fault in the eastern part of the Central Marmara Basin could not be followed by the total horizontal derivative method. The reason for this was considered to be the absence of sufficient density difference along this fault to produce high amplitude total horizontal derivative anomalies on both sides of the fault around the Central Marmara Basin. In addition, as a result of the 2D inversion process, it was observed that no sudden density change developed in the eastern part of the Central Marmara Basin. On the other hand, it was determined that the negative Bouguer gravity anomalies on the Central Marmara Basin were caused by both the lower boundary of the low-density sedimentary layer descending from 2.8 km to 7.4 km in this part, and the Moho boundary from 24.7 km to 28.6 km.